Exposure to trichloroethene at the workplace: possibilities of exposure control and risk assessment

Status:

completed 12/1996

Aims:

The suspicion which has been officially recognised since 1976 (incorporated in section IIIB of the german exposure limit list) that trichloroethene causes kidney tumours could to date be neither proved nor disproved. Current suspected cases of kidney tumours in persons exposed to trichloroethene - and the recognition that trichloroethene is metabolised in the same way in humans as it is when causing kidney tumours in animals - demonstrate the need for research. Goal: determining individual internal strain with exposure to trichlorethylene at the work place and deriving illness risk

Activities/Methods:

Determining individual exposure by means of technical measurements at selected work places, measurement of metabolites and biochemical terminal points (metabolite attachment to macromolecules); derivation of a risk quantification from the relationship between strain (trichloroethene concentration in the air) and demands (mercapturic acids in the urine, protein addition compounds in the blood, other kidney damage-inducing parameters)

Results:

A sufficiently sensitive GC-MS-method for quantification of trimetabolites in the urine of exposed persons indicative of kidney damaging effects has been developed. In humans and rats the proportional relationship of the various metabolites as well as the kinetics of discharge are different. All in all, the results contain indications of a lower risk as well as a higher risk of kidney tumours in humans in comparison with rats. The immunochemical attempt to detect the crucial protein addition compounds (chloracetyl) was not successful. With lower trichloroethene concentrations at actual work places acute toxicity was demonstrable.

Publications:

Bernauer, U.; Birner, G.; Dekant, W.; Henschler, D.: Biotransformation of trichloroethene: dose-dependent excretion of 2,2,2,-trichloro-metabolites and mercapturic acids in rats and humans after inhalation. Arch Toxicol (1996) 70, S. 338-346

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